Hertel 42259 11/16 in Cobalt Screw Machine Drill Bit

Product Description

The HERTEL 42259 is a screw machine length cobalt drill bit designed for drilling into hard and abrasion-resistant materials in production and maintenance environments. Built from M35 cobalt high-speed steel with an oxide straw finish, this bit delivers heat resistance and extended tool life compared to standard HSS tooling. The 135-degree split point reduces walking and decreases feed pressure at the start of the cut. At 4.8281 inches overall length with a 3.0781-inch spiral flute, the stub-length geometry provides added rigidity for accurate hole placement in metal fabrication, toolroom, and general machining applications. Licensed machinists and tooling specialists are the primary users.

This bit is sized at 11/16 inch (0.6875 inches) diameter and is suited for drilling hardened materials, heat-treatable alloyed steels, stainless steel, and titanium alloys. The screw machine length format is common on CNC machining centers, drill presses, and manual lathes where stub-length rigidity is required to maintain tolerance. The 3xD flute-to-diameter ratio supports chip evacuation in short-hole applications. It is sold individually and is appropriate for production shops, maintenance and repair operations, and toolrooms requiring consistent performance on difficult-to-machine alloys.

Key Features

• M35 cobalt construction resists heat buildup when drilling stainless steel, titanium alloy, and hardened materials
• 135-degree split point reduces thrust force and prevents bit walking on entry
• Oxide straw finish provides mild lubricity and corrosion resistance
• Screw machine (stub) length body adds rigidity and reduces deflection in tight setups
• Regular spiral flute geometry promotes consistent chip evacuation in short-hole drilling
• No coolant-through design — suitable for standard dry or flood-coolant external applications

Compatibility

Designed for use in standard drill chucks and collet systems accepting 11/16 inch shank diameter. Appropriate for CNC machining centers, drill presses, turret lathes, and manual milling machines where screw machine length tooling is specified. Primary workpiece materials include hardened materials, heat-treatable alloyed steels, stainless steel, and titanium alloy.

Installation Notes

Install and tighten securely in the chuck or collet before starting the spindle. Ensure the workpiece is firmly clamped before beginning the cut — unsecured material is a common cause of bit breakage and workpiece ejection. Select appropriate spindle speed and feed rate for the workpiece material and bit diameter per standard machining data references. Inspect the cutting edges for wear or chipping before each use, particularly after drilling hardened or abrasive alloys.